Study On Wave Field Distribution And Near-wellbore Filtration Features Under Low-frequency High-power Resonance Wave Recovery

Low-frequency high-power resonance wave enhanced oil recovery has a strong pertinence to the exploitation of heavy crude and low permeability reservoir. It can release near wellbore reservoir choke efficiently, and improve flowability of reservoir. Accordingly, the productivity of wells is increased. Also it has the advantages of low cost, well-adapted, and easy in operation and enviroplast. So it is an excellent EOR technology with a good prospect of application.In this paper, the solid/liquid coupling propagation theory of low-frequency high-power harmonic wave in porous media has been studied. The effects of vibration frequency, reservoir permeability, porosity and fluid viscosity on low-frequency vibration are researched through theoretical analysis. The synergetic effects of oil-water filtration theory and making fracture ability under low-frequency resonance wave are investigated in this thesis through laboratory experiment. Combine physical analogue with mathematical model, the one-dimensional and radial filtration patterns of the low-frequency resonance wave in porous medium are studied in this article. A coupled mathematical model of formation properties and vibration parameters are built to study the relation between various parameters and its final working effect. According to the mathematical model, the pressure profile is developed. The casing longitudinal vibration under low-frequency resonance wave is analyzed and longitudinal vibration characteristics are obtained by solving the oscillation equation. The research results show that low-frequency wave field is mainly affected by reservoir permeability and vibration frequency. The decay and scope rate of low-frequency amplitude increase along with the increasing frequency and permeability. Low-frequency vibration can decrease oil and water interfacial tension and change the core and fluid wettability, reduce the water cut of output fluid and improve the single phase flow and waterflooding effect obviously. Based on the above theoretical research and laboratory experiment, the process parameters of low-frequency high-power resonance wave EOR technology are optimized. And field experiment is carried out, production data before and after the test is monitored, the high speed data acquisition system is also established to test the vibration. The neutron attenuation is acquired and the response behavior is decided by analyzing the data acquired from surface monitoring system.This paper provides theoretical foundation for field construction. And it supplies a foundation for the study of high-power resonance wave that can make fractures and increase permeability with high efficiency, low cost and no pollution.